Uniform Office Spreadsheet (.uos)
The UOS (Uniform Office Spreadsheet) file extension is used for spreadsheets created in the Uniform Office Format (UOF), a Chinese-developed open standard for office productivity applications. Introduced in 2007, UOS files save data using XML and compression, making them similar to but not compatible with Microsoft Office Open XML and OASIS OpenDocument formats. These files can be opened by applications like OpenOffice Calc.